If he steps it up another notch, it gives us with other players as well ... a big hope now getting ready for the knockout stage. Because we know that players have not reached their highest spot yet. He is one of them.

SAO PAULO -- Michael Bradley is just shy of a marathon in this World Cup.

He has run more than any other player in Brazil and might be right up there with Luis Suarez among the most scrutinized.

The U.S. midfielder is taking the heat from fans and soccer pundits for his lack of offensive production through the three Group G matches. Yet the Americans reached the knockout rounds in consecutive World Cups for the first time with the help of his defense. And Bradley has coach Jurgen Klinsmann's utmost respect.

The American Outlaws even chanted "Michael Bradley! Michael Bradley!" after he was admonished by the referee for a studs-up tackle on Thomas Mueller in the 45th minute of Thursday's 1-0 loss to Germany in Recife.

"I am very, very satisfied with Michael in this tournament so far," Klinsmann said. "I know that he has another gear in him."

Bradley has covered a World Cup-leading 23.6 miles, or 38 kilometers. Chilean midfielder Marcelo Diaz is the only other player to go more than 36 kilometers, with three others having covered slightly more than 35.

Klinsmann challenged all his players Friday once the team returned to its training base and held a session under sunny skies at Sao Paulo Futebol Clube in preparation for Tuesday's knockout game against Belgium.

"I believe that in our team so far nobody can claim that he reached his 100 percent yet, so this is a very important message to the players that now prove it," he said. "This is what you worked for so long, so hard for it. Now take it one game at a time with total focus just to this one game, and after that game is done to the next game and make it happen. Is it doable? Absolutely."

The 26-year-old Bradley, who plays for Toronto FC in Major League Soccer, is starved for a goal this year on soccer's biggest stage. Some of his touches have been heavy. His most memorable moment so far might be when he gave up the ball to Eder late in stoppage time, starting the sequence that led to Portugal's equalizer in a 2-2 draw last Sunday in Manaus.

Not that it seems to have Klinsmann concerned. The Americans know they must find ways to generate more shots to put themselves in position to keep this special Brazilian run going beyond Tuesday in Salvador. Bradley is expected to connect better with captain Clint Dempsey, who in the last two matches has been the Americans' lone forward.

"If he already plays on this level right now, we came through this group because of his influence on the field," Klinsmann said, "then if he steps it up another notch, it gives us with other players as well ... a big hope now getting ready for the knockout stage. Because we know that players have not reached their highest spot yet. He is one of them, but overall I am very, very happy with him. The leadership is, I mean he has covered so much ground, he is all over the place. The defensive work that Michael puts in is absolutely outstanding."

And Klinsmann credits Bradley's efforts in the back as a big reason Germany was unable to get many opportunities.

Bradley is his own toughest critic.

"I'm certainly honest enough and hard enough with myself to know that it wasn't my sharpest night, but unfortunately they're not all going to be," he said after the Ghana game, a 2-1 victory. "And on those days it's still about finding every possible way to help your team."

Klinsmann has called on players at all positions to consciously think about moving upfield. The Americans realize full well it's going to take everybody, not just Bradley behind Dempsey, pushing the attack to give them the best opportunity to reach the quarterfinals for the first time in 12 years.

"We needed to do a better job at the beginning of the game of not letting them have the `German effect.' A lot of times teams will just sit back and allow them to come at you," midfielder Graham Zusi said. "We didn't really want them to do that. It took about 15-20 minutes for us to realize that we can knock the ball around as well.

"The first minutes of the game, impose yourself, step on their toes a bit, get in their face. I think that once we realized that we could play, we saw it turn around. We know that we can now. It's just a matter of doing it early on."